Ran pathway-independent regulation of mitotic Golgi disassembly by Importin-?.

ABSTRACT: To facilitate proper mitotic cell partitioning, the Golgi disassembles by suppressing vesicle fusion. However, the underlying mechanism has not been characterized previously. Here, we report a Ran pathway-independent attenuation mechanism that allows Importin-? (a nuclear transport factor) to suppress the vesicle fusion mediated by p115 (a vesicular tethering factor) and is required for mitotic Golgi disassembly. We demonstrate that Importin-? directly competes with p115 for interaction with the Golgi protein GM130. This interaction, promoted by a phosphate moiety on GM130, is independent of Importin-? and Ran. A GM130 K34A mutant, in which the Importin-?-GM130 interaction is specifically disrupted, exhibited abundant Golgi puncta during metaphase. Importantly, a mutant showing enhanced p115-GM130 interaction presented proliferative defects and G2/M arrest, demonstrating that Importin-?-GM130 binding modulates the Golgi disassembly that governs mitotic progression. Our findings illuminate that the Ran and kinase-phosphatase pathways regulate multiple aspects of mitosis coordinated by Importin-? (e.g. spindle assembly, Golgi disassembly).

SUBMITTER: Chang CC 

PROVIDER: S-EPMC6754406 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature